Stripper for fabrics



No Drawing. l

Patented June 16, 1931 Q UNITED STATES iriararrr OFFICE WOLF KBITCHEVSKYAND HAROLD C, PRO'TSMAN, OF CHICAGO, ILLINOIS, ASSIGNOBS TO RIT PRODUCTSCORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF DELA- WARE Ourinvention relates to a composition of matter intended for use as a colorremover or stripper for dyed fabrics.

Due to the extensive practice of this art, both commercially and inhouseholds, there is a large and growing demand for a product that willaccomplish the desired result in a satisfactory manner. The class ofchemicals most generally used for this purpose is that known assulphites, hydrosulphites and sulphoxylates. A most commonlyusedcomposition consists of a mixture of zinc dust and sodium bisulphite,which, in a water solution, evolves hydrogen and forms a chemical knownas zinc hydrosulphite. A well known chemical of this class is sodiumhydrosulphite of the general formula Na S O known commercially in thiscountry as lykopon, bleacan, decrolin, etc This chemical, when boiled inwater either alone or in the presence of an alkali or acid evolveshydrogen according to the equationENa S O and 2H O=2NaHSO and H Thissubstance is sold in large quantities for stripping'dyes and forreducing vat dyes in dyeing and tinting. The chemical is quiteefficient, but is very unstable due to its capacity of absorbing oxygenand moisture from the air, resulting in the liberation of hydrogen. Itis therefore necesary that the product be sold in sealed containers andthat it be used promptly by the purchaser.

Many attempts have been made to obviate this difiiculty and to stabilizethe substance. In one instance the sodium hydrosulphite is combined withformaldehyde resulting in the formation of sodium hydrosulphite-"formal-.l dehyde, otherwise known as sodium sulphoxylate. This-product issomewhat more stable than hydrosulphitealone but is. not stable in apractical sense.

Another method of 'efl'ecting stabilization is to form normalzincsaltsknown as zinc hydrosulphites or protoline or zinc sulphoxylatehydrosulphite. These represent an improvement over lykopon but they arenot stable and must be isolated from air and moisture J r In view of thefact that all of the substances heretofore mentioned are water soluble,it has Application filed April 30,

s'rnrrrnn ron rnnnrcs 1930. Serial No. 448,782;

been proposed that a desired result might be secured by forming theinsoluble derivatives, and zinc salts, known as basic zinc sulphoxyslate hydrosulphite has been developed, otherwise known as rongalite orformopon-extra. These substances are considerably more stable. in air,due to the fact that they are insoluble in water. However, in order touse them, they must be used in an acid solution .to neutralize the zincsalt and liberate the free acid. The result is a compound much weakerthan straight sodium hydrosulphite.

However, even these derivatives are not staments looking forward to thedevelopment of w a stripping substance that could be marketed inpackage-form and that would be stable 'under all atmospheric conditions,and be completely soluble.

As the result of our experiments, we have found that the main reason forthe decomposition of the hydrosulphite compounds was that the substancewashygroscopic and decomposes in the presence of air and moisture.

We have, therefore, determined that if the A hydrosulphite particles areenveloped in a water-proof orwater-resistant film, the oxygen of theair, and moisture will beexcluded and the substance will remain stableindefinitely.

In speaking of hydrosulphites, we include under that name allcompoundsthat belong to this class. It may include the salts of hydr0su1-furous acid of the general formula son- In also may include thedilferent salts of the condensation product hydrosulfurous acid or itssalts with formaldehyde which have the following formula son omon ormixtures thereof, known as formaldehyde sulphoxalic acid and its salts,whether sodium, zinc, calcium, bisulphuriccacid and its salts, theformula being SOaH cmon or mixtures thereof. These compounds aretechnically known as lykopon, which is sodium hydrosulphite, decrolin orprotolin,

which is zinc hydrosulphite-sulphoxylate, or

formopon, which is sodium sulphoxylate formaldehyde or basic zincsulphoxylate formaldehyde technically'known as formoponextra, rongalite,etc. There are many other formulae and many other technical means,- butfor brevity the substances are herein called hydrosulphites as theybelong generally to the hydrosulfite class,- the hypotheticalhydrosulfurous acid being the parent substance of the whole class. Wehave found that when sodiumhydrosulphite or one of the derivativesheretofore mentioned is intimately mixed with an oily substance theproduct will remain stable even when it is exposed to the air forpractically an indefinite period. An oily substance that will accomplishthis result may be a hydrocarbon such as petrolatum. kerosene, orparafline, or a metallic 'soapthat is insoluble in water, such asaluminum stearate or even an ordinary anhydrous soap, such as sodiumstearate, or sulphonated vegetable soap or a vegetable oil, such ascastor oil, corn oil, or a sulphonated oil, or a fatty acid like oleicacid, stearic acid, sulphonated fatty acid, etc., or a'naphthenic acidor a sulphonated petrolatum residue.

We have determined that when a quantity of any of the mentioned oilysubstances in excess of 2 9 27 of the total amount of hydrosulphite,depending on the character of the oily substance, is intimately mixedtherewith, an oily film is formed around'each particle of thehydrosulphite thus providing an encasing envelope that serves to excludeair and moisture for practically an indefinite period.

A product such as described can be used in that form in operations wherean aqueous solution is not necessary. However, where a water solution isrequired it will be found desirable to first supply to the water anagent that will serve to act on the oily substance, and release it fromits intimate association with the hydrosulphite unless the oilysubstance itself is soluble or disperses in an excess of w(ater. Thiswill permit the hydroetc. and formaldehyde emeea sulphite to enter intosolution and to act in the expected manner. 4

An agent that will act as required may consist of a chemical that willserve to emulsify the oily substance with the water. An oily substancesuch as paraffine, oil, vegetable oil or Wax may be emulsified bysulphonated soap, sulphonated oil, ordinary soap, neomerpin, which is asalt of a sulphonated alkylated polynuclear hydrocarbon, or sulphonatedpetroleum residues or sodium caseinate.

Or, the oily substance may be treated by a saponifying agent, such as analkali like lnerchandized in packages for household use it is desirablethat an agent be combined with the treated hydrosulphite having thecapacity for reacting with or acting upon the oily substance only whenthe mixture is placed in an excess of Water. The agent may have thecapacity of emulsifying the oily substance and causing it to form anemulsion with the water, or it may react with'the oily substance andsaponify it. In either case, the oily substance is detached from thehydrosulphite and the hydrosulphite is permitted to enter into solution.

An essential of the mixture is that an agent shall be selected that willbe dormant or inactive relative to the sulphite and its oily envelope solong as the compound remains in drymixture.

To illustrate, a compound contemplated in the last named disclosure mayconsist of 90 grams of sodium hydrosulphite and grams of petrolatum.Those are first intimately mixed so that substantially every particle ofthe hydrosulphite receives a coating or envelope of the oil material.When this is accomplished we add 5-30 grams of iso-propyl naphthalenesodium sulphonate, or sodium caseinate, or sulphonated oil, or sodiumricinoleate or any similar agent having emulsifying properties. Thiscompound is stable practically indefinitel and, when added to water,acts in the esired manner. We may also add chemicals to provide an acidor alkali reaction like soda ash or bisulphite of soda or we may add aninert substance such as salt. A

In the event that aflsaponifiable oil'or a other words, thehydrosulphite is intimately mixed with the oily substance whichmayconfatty acid is used, the process is similar. In

combine in solid mixture a quantity of soda ash, anhydrous borax, orammonium carbonate in sufficient proportions to saponify the oil; or ina less proportion, in which case part of the oil may be saponified, thusforming a quantity of soap that will emulsify the remainder of the oil.Or we may prefer to utilize a substantially larger quantlty of thesaponifying agent, that is, more than sulficient to saponif the oil, inwhich case we provide an excess 0 alkali in the bath which will assistthe hydrosulphite reaction.

In the compound last described, it may occur under extreme climaticconditions that there will 'be a limited reaction of the solid substancebefore the compound is added to a bath but this willresult merely in theformation of a small quantity of soap which will act to emulsify theoily substance. Even though all the oily substance became saponified,the so-formed soap would envelope the hydrosulphite and prevent thedeterioration of the active ingredient. Soap is water resistant to asmall amount of water, although soluble in an excess of water.

It may be found desirable to utilize a sulphoxylate formaldehyde insteadof plain so-. diumhydrosulphite in which case it will be.

found necessary to provide an acid reacting bath. This may, and probablywill be, ef fected by providin a solid mixture of the sulphoxylateformal ehyde, an oily substance that will encase the particles of thesulphoxylate formaldehyde, and a solid salt that may or may not reactwith the oily substance as desired. This 1 compound together with anemulsifyi or sa onif in a cut, either in Hg P y a f the solid mixture orin the so ution will accomplish the purpose of providing an effectivestripper that may be sold in packages or otherwise withoutdeterioration.

We may prefer to also add to the solid compound other substancessuch assolvents, assistants, penetrators, and fillers, as long as 7 any suchadded substance does not interfere With the function of the oilysubstance.

We have not attempted herein to specify or a mention all possiblesubstances that may be 55.

used or that will function to'protect the hydrosulphite fromdeterioration, dependingon mixture of a stripping chemical of the hyfilmdrosulfite class, a substance substantially insoluble in water andbelonging tothe class of oils, fats and waxes that will encase theindividual particles of the stripping chemical and tend to exclude airand moisture a therefrom, and an agent that will be substantially inertrelative to said substance when the materials are inanhydrous mixture,and that will in a water solution release the sub stance from itsassociation with said stripping chemical and form an emulsion withthewater.

2. A composition of matter consisting of a mixture of .a strippingchemical of the hydrosulfite class, a substance substantially insolublein water and belonging to the class of oils, fats and waxes that willencase the individual particles of the stripping chemical, and tend toexclude air and moisture therefrom, and an agent that will in a watersolution emulsify said substance with the water and release the saidsubstance from its association with said stripping chemical and permitsaid substance to enter into water solution.

3. A composition of matter consisting of a chemical of the hydrosulfiteclass capable of evolving hydrogen, a substance substantially insolublein water and belonging to the class of oils, fats and waxes envelopingthe particles of said chemical, an agent that will in a water solutioncause said oily substance to form an emulsion with-the water, and anacid-reacting substance that will in water solution assist said chemicalin evolving hydrogen; V

4. A composition of matter consisting of a solid mixture of a chemicalbelonging to the hydrosulphite class, a petroleum hydrocarbon and anemulsifying agent capable of act ing on said hydrocarbon in a water bathto cause the hydrocarbon to be released from the hydrosulphite and causeit to. form an emulsion with the water.

5. A composition of matter that is stable under ordinary climaticconditions, consisting of a mixture of a stripping chemical of thehydrosulfite class when it enters into solution and. a substancesubstantially insoluble in water and belonging to the class of oils,fats and waxes that will encase the individual particles of thestripping chemical and tend to exclude air and moisture therefrom,.andan agent that will in a water solutlon disperse the oily character ofthe substance and free the stripping chemical.

6. A composition of matter consisting of a all the particles of thehydrosulphite, and isopropyl naphthalene sodium sulphonate in quantitysufficient to cause the petrolatum to form an emulsion in a' watersolution and thereby release the hydrosulphite from the In testimonywhereof we have alfixed our signatures.

' WOLF- KRITOHEVSKY.

HAROLD C. PRUTSMAN.

